Julie Schenecker, 53, is on trial in Tampa for killing 16-year-old Calyx and 13-year-old Beau in January of 2011.

The Scheneckers are now divorced. During his questioning by prosecutors in Hillsborough County Court, Parker Schenecker did not mention Julie Schenecker by name, instead calling her "the defendant" or his "ex-wife."

He was an Army colonel deployed in the Middle East when his children were killed.

Defense attorneys say Julie Schenecker suffered from bipolar disorder and depression. She has pleaded not guilty by reason of insanity to two counts of first-degree murder.

Parker Schenecker did not show any emotion as he testified for a little more than an hour. He identified various items from the family's home in photographs, and affirmed that the handwriting in a spiral-bound notebook was Julie's.

The 50-year-old read one sticky note aloud: "Tuesday, Feb. 1 Beau is in the van (on the way to practice) Calyx is in her bed tried to make her comfortable."

Prosecutors said the note was written by Julie Schenecker and detailed the location of the teens' bodies.

Parker said that he had no concerns about the kids' safety with their mother while he was deployed, even though his wife had suffered from mental illness, was taking pills and uncharacteristically drinking. Julie Schenecker and Calyx were also at odds with each other, he said, and he thought the situation would soon be under control because the teen was supposed to attend a boarding school.

"To let the situation settle down," he said.

Earlier in the day, Tampa Police crime scene analyst Matthew Evans said that Julie Schenecker had written in her journal that she thought her children would inherit her bipolar disorder and that she was rescuing them from depression and mental illness.

"I believed I've saved them from the pain," Julie Schenecker wrote, according to Evans. "I wish this on nobody."

Schenecker wrote of "going to heaven," and she both apologized to and chastised Parker Schenecker, the analyst testified.

"You didn't teach the kids to be compassionate," she wrote. Evans said Julie Schenecker also described how she had stayed in bed for seven weeks, with none of her family spending time with her. "Neither were you," she wrote of her husband.

"I sense divorce is inevitable," she also wrote, according to Evans' testimony. "I can't live alone."

Her writings show she intended to commit suicide by shooting herself, inhaling carbon monoxide or taking pills.

"I don't believe I could ever recover or make up for my failures over the years," she wrote.